One vertex per element, one color per generator, with an edge from x to x·s.
(2,4)(5,6,8,7)(9,10,14,20,15,21,13,19)(11,17,23,16,25,31,24,32)(12,18,28,35,29,36,27,34)(22,33,37,30,38,40,26,39)(5,7,8,6)(9,11)(10,16)(12,26)(13,23)(14,24)(15,25)(17,20)(18,33)(19,31)(21,32)(22,27)(28,38)(29,37)(30,34)(35,39)(36,40)(1,2,3,4)(9,11)(10,17)(12,22)(13,24)(14,23)(15,25)(16,20)(18,33)(19,32)(21,31)(26,27)(28,37)(29,38)(30,35)(34,39)(36,40)(9,12,14,28,15,29,13,27)(10,18,20,35,21,36,19,34)(11,22,23,37,25,38,24,26)(16,30,31,40,32,39,17,33)(9,13,15,14)(10,19,21,20)(11,23,25,24)(12,27,29,28)(16,31,32,17)(18,34,36,35)(22,37,38,26)(30,40,39,33)A Cayley diagram is a choice, not a fact about the group. Another drawing of this group — in a book, or on a different generating set — may look nothing like this one.